In recent years, in connection with the size and weight reduction of the mobile computing devices represented by a cellular phone, the digital camera, etc. and the information storage medium represented by the memory card etc., densification of the semiconductor device built into these is advanced. The thickness reduction of the semiconductor chip which forms a semiconductor device is indispensable to the densification of a semiconductor device. The multi-stage laminated constitution which accumulates the semiconductor chips made thin to many stages, such as two stages, or three stages is also developed, and densification of the semiconductor device is advanced further.
The method which laminates the semiconductor chip of the second stage via a paste state binding material to the region inside a plurality of electrodes formed, for example on the main surface of the semiconductor chip of the first stage is one of the methods which paste up between the semiconductor chips accumulated to many stages. However, by this method, according to the press load at the time of mounting the semiconductor chip of the second stage, a paste state binding material may overflow between up and down semiconductor chips horizontally (to a plurality of electrodes of the semiconductor chip of the first stage), and may cover the electrode of the main surface of the lower semiconductor chip. Since the semiconductor chip is thin, the paste state binding material may crawl up to a main surface from the back surface through the side face of the upper semiconductor chip. Since the binding material is paste state, in addition to the accuracy of thickness being low, the semiconductor chip mounted on the binding material may incline.
As a method which solves such trouble, film-like adhesion members, such as a die attach film (Die Attach Film: henceforth DAF), are developed, for example, and it contributes to the miniaturization and thickness reduction of a semiconductor device, and multi-stage lamination of a semiconductor chip. There are Cut and Reel Method and Wafer Back Surface Sticking Method in the adhesion method of the semiconductor chip using DAF, for example. Cut and Reel Method is a method of transporting and sticking on the chip mounting surface of a lower semiconductor chip DAF cut to chip size, and sticking an other semiconductor chip on it. On the other hand, the above-mentioned Wafer Back Surface Sticking Method is a method of cutting the DAF simultaneously with a semiconductor chip at the time of dicing after sticking DAF so that the whole surface of the back surface of the semiconductor wafer may be covered, and sticking the semiconductor chip on the chip mounting surface of the lower semiconductor chip by DAF of the back surface.
About a die-bonding technology, Japanese Unexamined Patent Publication No. Hei 8-236554 (Patent Reference 1) has a description, for example. The technology of obtaining the semiconductor device which equipped the back surface with the thermoplastic electrically conductive polyimide layer, separating the wafer per chip after forming the thermoplastic electrically conductive polyimide layer on the back surface of the wafer with a spin coat method is disclosed.
[Patent Reference 1] Japanese Unexamined Patent Publication No. Hei 8-236554